The question of whether proprietary closed source code is present inside open source code is a huge issue. It sits at the crux of the SCO battle against Linux and it is also at the center of another controversy surrounding an open source effort to create a free clone of Microsoft's Windows operating system.

ReactOS is part of a decade old effort to replicate a Windows operating system as an open source or free software based system. It's not the only effort trying to duplicate Windows type functionality on an open source system. The Wine project which began in 1993 is a similar effort but unlike ReactOS its goal is not to produce an entire operating system, but rather just allow Windows applications to run on Linux. Certain elements of Wine are also part of ReactOS.

In January of this year, allegations were levied against ReactOS that some code may well have been inappropriately taken from Windows NT and found its way into the open source clone. In response the ReactOS development team stopped development and downloads and began a detailed audit of their code base.

The result?

"To say it in simple words: There is clearly NO code which is directly copy-pasted from MS kernel code," the ReactOS Web site now declares.

Developers have not yet however completed a complete audit of the 2 million plus lines of C code that is ReactOS, though the 15 percent that has been checked is now considered to be "clean code."

"This does not mean that 85 percent of code are affected," the ReactOS Web site states. "We are working on it, we are working on checking the code and finding suspicious code which might be derived from leaked code or reverse engineering. But this is lots of work and as we can not compare with Windows Source - the methods used for auditing are VERY complicated. So please, give us time."

A Microsoft spokesperson told internetnews.com that it had no comment on the React OS project.

ReactOS Project Coordinator Steven Edwards told internetnews.com that the project has not been in contact with Microsoft in any official manner. That's not to say they haven't had any contact with Microsoft personnel though.

"We have talked to many people who work at Microsoft at trade shows and our developers know lots of people who work at Microsoft," said Edwards. "They all seem very positive and supportive of what we are doing in principle."

Among the potential sources of where ReactOS developers may have seen Windows source code is from the 2004 leak of Windows NT onto P2P file sharing networks.

"They won't be disallowed from contributing however anyone that has seen Windows code is asked not to contribute code in the area they have seen," Edwards explained. "You have to understand the Windows code is like 30 million lines that's no reason to deny them access to contribute to parts they have not seen."

The audit effort is expected to be completed this year, and Edwards also hopes to release the 0.3 version which would be the release that is really usable for the power user or geek and not just for the developer.

"It will be more stable, have better hardware support and provide tcp/ip client networking services," Edward commented. "A user should be able to get online, check email, chat and install and run a few of the most common Win32 applications."

Edwards argued that legal challenges are only a small factor at this point. The big challenge is enabling ReactOS to be usable in the business world. To do that, the project is going to need more help.

"Right now we really need more developers and users who can help with debugging. We are only a small team of 20 developers and maybe 100 or so active users," Edwards said. "There are maybe 100,000+ other people that have tried ReactOS but do not test it on a regular basis."